Influence of Geofoam Infill Trenches in Attenuation of Ground Vibrations Induced During Dynamic Compaction

Abstract

Dynamic compaction (DC) is a widely adopted ground improvement technique in the field for improving geotechnical characteristics of loose soil deposits. The technique involves repeated dropping of a heavy tamper weighing about 5–40 t onto the soil surface from a predetermined height of 5–25 m. At the moment of tamper blow on soil surface, the kinetic energy of tamper is transformed into seismic waves, which subsequently transmits into the underlying soil mass in the form of compression waves and shear waves and along the soil surface as Rayleigh waves. Thus, while implementing DC at the site, adequate measures must be adopted to prevent damage of adjacent infrastructural facilities under the impact of Rayleigh waves induced during DC. The present study focuses on establishing the efficacy of infill trenches with geofoam inclusions in intercepting the corresponding wave propagation during DC. Laboratory model tests were conducted in this regard on a representative loose sand deposit prepared at relative density of 35%. A custom-developed actuator was used in this regard. Model tests were performed using circular tampers on the loose sand bed, and corresponding ground vibrations recorded by accelerometers were analyzed to derive peak ground vibration (PGV) values. Subsequent model testing was performed with and without geofoam barrier, and the corresponding ground vibrations were analyzed. Based on the analysis and interpretation of test results, the efficiency of geofoam barriers in attenuation of ground vibrations induced during DC could be successfully established. The geofoam barrier was found to exhibit up to 65% efficiency in attenuating induced ground vibrations.